This is an application for an International Clinical, Operational, and Health Services Research Training Award from the National Institute on Drug Abuse and Fogarty International Center. It aims to increase the count of quantitatively adept scientists who can lead epidemiological studies of tobacco, cocaine, and other drugs, associated infections & medical consequences. Tobacco smoking and other drug use are health-related behaviors of growing importance, quantified in terms of burden of disease and disability in the U.S. and overseas. There is a real shortage of scientists with suitable training and research experience for NIDA-oriented epidemiological studies, not only within the U.S., but also in Latin America and elsewhere. Demand for NIDA-oriented epidemiological surveillance and probing epidemiological studies surpasses the supply of scientists. Peru is located in a major coca cultivation region in Latin America. Like most countries in the region, it faces important health and social problems associated with use of coca leaf products (e.g., cocaine hydrochloride powder) and other drugs such as tobacco. Some recent initial epidemiological surveys in Peru have confirmed an impression of increasing trends in use of coca paste (pastabas), a product of intermediate between coca leaf and cocaine HCL, sometimes mixed with kerosene and other toxic contaminants. Peru also is the site of an existing multi-faceted research and research training collaboration between Johns Hopkins University (JHU) and Universidad Peurana Cayetano Heredia (UPCH). Collaborations already link the UPCH faculty and trainees with a NIDA-supported T32 institutional NRSA training program, and with a separate program for research and training on epidemiology of infectious origins. The proposed award will sustain and extend this collaboration with an initial intermediate-length orientation course and faculty-supervised research experiences for a minimum of 20 predoctoral and postdoctoral Peruvian trainees at the UPCH site. Two will be selected for Ph.D. training at JHU, one PDF for Master of Science training, and three PDF for advanced postdoctoral training and PDF certificates awarded by JHU. They all will return to Peru sites for summer and thesis or PDF research training after completion of required coursework at JHU. The award also will support thesis and research projects for returning students and collaborating faculty members.